Surface　functional　modification　through　small　organic　molecules　to　form　surface　complex　which　possess　unique　electronic　and　optical　properties,　is　a　hopeful　strategy　in　activating　BiOCl-0　1　0　for　visible　light　harvesting.　However,　the　significant　charge　transfer　between　surface　complex　and　BiOCl-0　1　0　in　photocatalytic　process　is　vague.　In　this　work,　we　ingeniously　design　a　facile　repeat　experiment　to　obtain　reliable　information　on　charge　transfer　mechanisms　and　structure-reactivity　relationships　between　surface　complex　and　BiOCl-0　1　0　under　reaction　condition,　Interestingly,　this　charge　transfer　gives　rise　to　the　formation　of　defects　which　are　protected　by　a　disordered　outer　layer　on　surface.　Moreover,　the　introduction　of　defects　plays　a　vital　role　in　photocatalytic　and　photoelectric　performance,　which　can　be　verified　by　DFT　calculations.　Our　current　work　is　expected　to　offer　new　insight　into　charge　transfer　between　surface　complex　and　substrates　for　better　understanding　to　photocatalytic　reactions　and　for　rational　design　and　synthesis　of　photocatalyst　with　high　activity.　(C)　2014　Elsevier　B.V.　All　rights　reserved.